Acute effects of cadmium and copper on survival, oxygen consumption, ammonia-N excretion, and metal accumulation in juvenile Exopalaemon carinicauda.

Ridgetail white prawn (Exopalaemon carinicauda), a commercially important species in China, is a potential candidate for evaluating impairments caused by environmental pollutants in coastal and estuarine areas. The main purpose of the present study was to investigate the acute effects of cadmium (Cd) and copper (Cu) on survival, oxygen consumption, ammonia-N excretion, and metal accumulation in E. carinicauda. The feasibility of using this species for pollution monitoring was also evaluated. Results showed that the median lethal concentrations (LC50) for 24h, 48h, 72h, and 96h were 0.66mg/L, 0.379mg/L, 0.343mg/L, and 0.258mg/L for Cd, and 0.932mg/L, 0.748mg/L, 0.725mg/L, and 0.712mg/L for Cu. Cd exposure (0.66mg/L) caused an inhibition in oxygen consumption of 21.1 percent and an increase in ammonia-N excretion of 47.1 percent, thereby decreasing the atomic ratio of oxygen consumed to nitrogen consumed (O:N ratio) of 46.32 percent relative to the control. Cu exposure (0.932mg/L) also resulted in an inhibition in oxygen consumption of 34.8 percent and a decrease in the O:N ratio of 23.9 percent in relation to the control, but the ammonia-N excretion was not influenced by the Cu exposure. Concentration-depended accumulation was observed in the experimental animals, which a maximum of 244.8 folds and 1.1 folds increase of mental concentration was measured upon exposure to 24h LC50 of Cd and Cu for 24h, respectively. The change in O:N ratio indicated an alteration in energy utilization. Based on its sensitivity to heavy metals and its availability all year round, E. carinicauda can be used as a test organism to monitor for metal pollution.